Winding battery cell and battery
By creating grooves in the curved sections of the wound battery cell to construct lithium-ion transport channels, the problem of lithium plating at battery corners is solved, the charging and discharging capacity is improved while maintaining energy density, and the shortcomings of existing technologies are overcome.
Patent Information
- Application Number
- CN202422860478.3
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-11-22
- Publication Date
- 2025-11-11
- Estimated Expiration
- 2034-11-22
AI Technical Summary
In wound batteries, the anode CB is often smaller than the cathode CB at the cell corner, leading to lithium plating, which affects the battery's safety and cycle performance. Existing technologies address this by increasing the N/P ratio of the outer cathode ring, but at the cost of energy density.
A first groove and a second groove are set at the corner of the wound cell to construct a lithium-ion transport channel, improve the lithium-ion transport capability, and reduce the thickness of the electrode sheet while taking into account the energy density.
It improves the lithium-ion transport capability at corners, reduces lithium plating, ensures the energy density of the battery cell, and solves the shortcomings of traditional methods.
Smart Images
Figure CN223539659U_ABST
Abstract
Description
Technical Field
[0001] This application relates to the field of battery technology, and in particular to a wound battery cell and battery. Background Technology
[0002] In wound batteries, at the corner position (i.e., the bending area of the cell), the anode CB is often smaller than the cathode CB, which makes lithium plating more likely at the outer corner position, affecting the safety and cycle performance of the battery.
[0003] In existing technologies, increasing the N / P ratio of the outer cathode ring is used to address the aforementioned problems. However, this approach comes at the cost of reduced cell energy density. The increased weight of the cathode coating on one side leads to an overall increase in cell thickness. Furthermore, the corners are subject to stress crossover during the formation stage, resulting in poor contact between electrodes and insufficient lithium intercalation space. Poor contact between electrodes also increases ion transport resistance, potentially exacerbating lithium plating in later stages of cycling. Lithium dendrites can then puncture the separator, causing short circuits, overheating, and fires. Utility Model Content
[0004] This application aims to address at least one of the technical problems existing in the prior art. To this end, in a first aspect, this application proposes a wound battery cell that, while maintaining energy density, can alleviate lithium plating at corner positions, thus overcoming the shortcomings of traditional methods.
[0005] Secondly, this application proposes a battery that uses the aforementioned wound cell.
[0006] According to the first aspect of this application, a wound battery cell includes:
[0007] The battery cell body includes a positive electrode plate and a negative electrode plate, which are stacked and wound together. Along the winding direction, the positive electrode plate and the negative electrode plate include alternating straight sections and curved sections.
[0008] Wherein, at least a portion of the bent section of the positive electrode and / or at least a portion of the bent section of the negative electrode are provided with a first groove and a second groove, the first groove being located at least on the side of the bent section near the center of the cell body, and the second groove being located on the groove wall of the first groove.
[0009] The wound battery cell according to the first aspect of the present application has at least the following beneficial effects:
[0010] The wound battery cell in this application features a first and a second groove at the corner, which effectively creates a lithium-ion transport channel, improves the lithium-ion transport capacity at the corner, thereby enhancing charge and discharge capabilities and reducing lithium plating at the corner. Simultaneously, the first and second grooves reduce the electrode thickness, which helps ensure the energy density of the battery cell.
[0011] In summary, the wound cell in this application can alleviate lithium plating at corner positions while maintaining energy density, thus overcoming the shortcomings of traditional methods.
[0012] According to some embodiments of this application, the depth of the first groove decreases layer by layer along a direction away from the center of the cell body.
[0013] According to some embodiments of this application, the cross-sectional profile of the first groove in the width direction is at least one of V-shape, arc shape and U-shape.
[0014] According to some embodiments of this application, the maximum width of the first groove decreases or remains the same layer by layer along the outer ring of the battery cell body towards the center.
[0015] According to some embodiments of this application, both the positive electrode and the negative electrode include a current collector and an active material layer. The active material layer is disposed on both sides of the current collector. The first groove and the second groove are both disposed on the active material layer. Furthermore, the maximum depth of the first groove to the surface of the active material layer is... The thickness H of the active material layer satisfies: 0.01H ≤ ≤0.5H.
[0016] According to some embodiments of this application, both the positive electrode and the negative electrode include a current collector and an active material layer. The active material layer is disposed on both sides of the current collector. The first groove and the second groove are both disposed on the active material layer, and the maximum depth of the second groove to the surface of the active material layer is... The thickness H of the active material layer satisfies: 0.2H ≤ ≤0.8H.
[0017] According to some embodiments of this application, the curved segment is provided with a plurality of first grooves along the winding direction, and / or, along the length direction of the curved segment, a plurality of second grooves are provided in the first grooves.
[0018] According to some embodiments of this application, the angle φ between the length direction of the second groove and the length direction of the first groove satisfies: 0°≤φ≤90°.
[0019] According to some embodiments of this application, the first groove and the second groove are also provided on the side of the curved section away from the center of the cell body.
[0020] The battery according to the second aspect of this application includes the wound cell of any of the above embodiments.
[0021] The battery according to the second aspect embodiment of this application has at least the following beneficial effects:
[0022] The battery in this application features a first and a second groove at the corner, which effectively creates a lithium-ion transport channel, improving the lithium-ion transport capacity at the corner and thus enhancing charge and discharge capabilities while reducing lithium plating at the corner. Simultaneously, the first and second grooves reduce the thickness of the electrode sheets, which helps ensure the energy density of the battery cell. Therefore, while maintaining energy density, it alleviates lithium plating at the corner, addressing the shortcomings of traditional methods.
[0023] Additional aspects and advantages of this application will be set forth in part in the description which follows, and some of these additional aspects and advantages will become apparent from the description or may be learned by practice of this application. Attached Figure Description
[0024] The present application will be further described below with reference to the accompanying drawings and embodiments, wherein:
[0025] Figure 1 This is a schematic diagram of one structure of the wound battery cell in this application;
[0026] Figure 2 This is a structural unfolded sectional view of the curved section in this application;
[0027] Figure 3 This is a schematic diagram of one structure of the first groove and the second groove in this application;
[0028] Figure 4 This is a schematic diagram of the first possible structure of the second groove in this application;
[0029] Figure 5 This is a schematic diagram of a second structure for the second groove in this application;
[0030] Figure 6 This is a schematic diagram of the third structure of the second groove in this application.
[0031] In the picture:
[0032] 100-Positive electrode plate;
[0033] 200-Negative electrode;
[0034] 301-Straight section, 302-Bent section, 303-Current collector, 304-Active material layer;
[0035] 3021 - First groove, 3022 - Second groove. Detailed Implementation
[0036] The embodiments of this application are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this application, and should not be construed as limiting this application.
[0037] In the description of this application, it should be understood that the orientation descriptions, such as up, down, front, back, left, right, etc., indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation. Therefore, they should not be construed as limitations on this application.
[0038] In the description of this application, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. The use of "first" and "second" in the description is merely for distinguishing technical features and should not be construed as indicating or implying relative importance, or implicitly indicating the number of indicated technical features, or implicitly indicating the order of the indicated technical features.
[0039] In the description of this application, unless otherwise expressly defined, terms such as "setup," "installation," and "connection" should be interpreted broadly, and those skilled in the art can reasonably determine the specific meaning of the above terms in this application in conjunction with the specific content of the technical solution.
[0040] In the description of this application, the terms "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., refer to specific features, structures, materials, or characteristics described in connection with that embodiment or example, which are included in at least one embodiment or example of this application. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.
[0041] Reference Figures 1 to 3 Embodiments of this application propose a wound battery cell, comprising:
[0042] The battery cell body includes a positive electrode 100 and a negative electrode 200, which are stacked and wound together. Along the winding direction, the positive electrode 100 and the negative electrode 200 include alternating straight sections 301 and bent sections 302.
[0043] Wherein, at least a portion of the bent section 302 of the positive electrode 100 and / or at least a portion of the bent section 302 of the negative electrode 200 are provided with a first groove 3021 and a second groove 3022, the first groove 3021 being located at least on the side of the bent section 302 near the center of the cell body, and the second groove 3022 being located on the groove wall of the first groove 3021.
[0044] It is understood that the wound battery cell in this embodiment has multiple configuration methods. For ease of description, the side closer to the center of the battery cell body is defined as the inner side, and the opposite side as the outer side. The configuration methods of the wound battery cell include:
[0045] The positive electrode 100 and negative electrode 200 of the wound cell are provided with a first groove 3021 and a second groove 3022 on both the inner and outer sides of all the bending sections 302;
[0046] Alternatively, the positive electrode 100 and negative electrode 200 of the wound cell are provided with a first groove 3021 and a second groove 3022 on the inner side of all the bending sections 302;
[0047] Alternatively, the positive electrode 100 and negative electrode 200 of the wound cell are provided with a first groove 3021 and a second groove 3022 on the outer side of all the bent sections 302;
[0048] Alternatively, the positive electrode 100 and negative electrode 200 of the wound cell are provided with a first groove 3021 and a second groove 3022 on both the inner and outer sides of the partial bending section 302;
[0049] Alternatively, the positive electrode 100 and negative electrode 200 of the wound cell are provided with a first groove 3021 and a second groove 3022 on the inner side of a portion of the bent section 302;
[0050] Alternatively, the positive electrode 100 and negative electrode 200 of the wound cell are provided with a first groove 3021 and a second groove 3022 on the outer side of the partially bent section 302;
[0051] Alternatively, the wound cell may have a first groove 3021 and a second groove 3022 only on the positive electrode 100 or the negative electrode 200.
[0052] Those skilled in the art can make flexible settings according to actual needs.
[0053] Understandably, in a wound cell structure, the electrodes at the curved sections tend to adhere completely together under tension, resulting in insufficient space for electrolyte storage. However, the wound cell in this application, with its first groove 3021 and second groove 3022 at the corners, creates space for electrolyte storage, effectively constructing lithium-ion transport channels, improving lithium-ion transport capacity at the corners, thereby enhancing charge / discharge capability and reducing lithium plating at the corners. Simultaneously, the first groove 3021 and second groove 3022 reduce the electrode thickness, which helps ensure the cell's energy density.
[0054] In summary, the wound battery cell in this application can alleviate lithium plating at corner positions while maintaining energy density, thus overcoming the shortcomings of traditional methods.
[0055] Reference Figure 2 and Figure 3 In some embodiments of this application, the depth of the first groove 3021 decreases layer by layer along the direction away from the center of the cell body. It is understood that the closer to the center, the more difficult it is for the electrolyte to enter. This embodiment, by increasing the depth of the first groove 3021 near the center, helps to increase the amount of electrolyte contained in the center of the wound cell. Furthermore, increasing the depth of the first groove 3021 allows for a reduction in the thickness of the positive electrode 100 and negative electrode 200 without affecting their performance, enabling them to fit more tightly together and simultaneously improving lithium-ion transport capacity, thereby improving the battery's energy efficiency (ED).
[0056] In some embodiments of this application, the cross-sectional profile of the first groove 3021 in the width direction is at least one of V-shape, arc shape and U-shape.
[0057] In this embodiment, by setting the cross-sectional profile of the first groove 3021 to a V-shape, arc shape, or U-shape, a buffered deepening of the groove wall can be achieved. Since the positive electrode 100 and negative electrode 200 of the wound battery cell are stacked and wound, they typically have multiple bending sections 302; therefore, the number of first grooves 3021 is usually also multiple. In actual installations, some of the first grooves 3021 of the wound battery cell can be designed as V-shapes, some as arc shapes, or some as U-shapes.
[0058] It is understandable that the arc design of the cross-sectional profile of the first groove 3021 can be a semi-circle or an arc with other curvatures.
[0059] In some embodiments of this application, the maximum width of the first groove 3021 decreases or remains the same layer by layer along the outer ring of the cell body towards the center.
[0060] Since the wound cell is made by stacking and winding positive electrode 100 and negative electrode 200, the wound cell has a multi-layer structure along the thickness direction, consisting of alternating positive electrode 100, negative electrode 200, positive electrode 100, and negative electrode 200 (the actual structure also includes a separator, but since the structural design of this embodiment does not involve the separator, and the separator is common knowledge, it is not mentioned or described in detail here). From the outside to the inside, the corner radius of each layer is different, and the bonding area between the positive electrode 100 and the negative electrode 200 also decreases layer by layer. In this embodiment, by designing the width of the first groove 3021 to decrease layer by layer or to keep it constant, it is convenient to ensure the bonding of the positive electrode 100 and the negative electrode 200, and can effectively accommodate the electrolyte and improve the lithium-ion transport capability.
[0061] It is understandable that in the aforementioned embodiments, the groove wall of the first groove 3021 is deepened in a buffered manner, thus the groove opening of the first groove 3021 has the largest width. When the first groove 3021 is set to be consistent layer by layer, that is, the size of the first groove 3021 in each curved segment 302 remains the same. However, when the width of the first groove 3021 is designed to decrease layer by layer, that is, from the outside to the inside, the groove opening width of the first groove 3021 decreases layer by layer, and the depth of the first groove 3021 can remain the same or decrease layer by layer, as long as it can meet the function of constructing a lithium-ion transport channel.
[0062] Reference Figure 2 and Figure 3 In some embodiments of this application, both the positive electrode 100 and the negative electrode 200 include a current collector 303 and an active material layer 304. The active material layer 304 is disposed on both sides of the current collector 303, and the first groove 3021 and the second groove 3022 are both disposed on the active material layer 304. Furthermore, the maximum depth of the first groove 3021 to the surface of the active material layer 304 is... The thickness H of the active material layer 304 satisfies: 0.01H ≤ ≤0.5H.
[0063] By increasing the depth of the first groove 3021 Within the aforementioned range, the first groove 3021 does not penetrate the active material layer 304, thus preserving sufficient active material layer 304 to construct a lithium-ion transport channel. The maximum depth of the first groove 3021... It can be set to 0.01H, 0.1H, 0.15H, 0.2H, 0.5H, etc.
[0064] In some embodiments of this application, the maximum depth from the second groove 3022 to the surface of the active material layer 304 is... The thickness H of the active material layer 304 satisfies: 0.2H ≤ ≤0.8H.
[0065] Since the second groove 3022 is formed on the wall of the first groove 3021, that is, a further deepening based on the depth of the first groove 3021, by adopting the structural setting of this embodiment, by limiting the depth of the second groove 3022 to the above-mentioned range, penetration of the active material layer 304 and thus affecting battery performance can be avoided. The maximum depth of the second groove 3022... It can be set to 0.2H, 0.4H, 0.5H, 0.6H, 0.8H, etc.
[0066] It should be noted that when setting the depth of the first groove 3021 and the second groove 3022, the common depth needs to be less than the thickness H of the active material layer 304, so as to avoid penetrating the active material layer 304.
[0067] In some embodiments of this application, the curved section 302 is provided with a plurality of first grooves 3021 along the winding direction, so that in the corner area, a plurality of lithium-ion transport channels can be constructed between each layer of positive electrode 100 and negative electrode 200, which is beneficial to improving the charging and discharging capability.
[0068] In some embodiments of this application, a plurality of second grooves 3022 are provided in the first groove 3021 along the length direction of the curved section 302.
[0069] It is understandable that the curved section 302 corresponds to the corner area of the wound cell. In the corner area, the first groove 3021 may close due to tension. In this embodiment, by setting multiple second grooves 3022, this situation can be effectively avoided, and a lithium-ion transport channel can be effectively constructed.
[0070] Reference Figures 4 to 6 In some embodiments of this application, the angle φ between the length direction of the second groove 3022 and the length direction of the first groove 3021 satisfies: 0°≤φ≤90°.
[0071] Reference Figure 4 and Figure 5 When the included angle φ is 0°, that is, the length directions of the first groove 3021 and the second groove 3022 are kept parallel. In this case, multiple second grooves 3022 can be set along the width direction of the first groove 3021.
[0072] Reference Figure 6 When the included angle φ is 90°, that is, the length directions of the first groove 3021 and the second groove 3022 are perpendicular to each other, in this case, multiple second grooves 3022 can be provided along the length direction of the first groove 3021.
[0073] The included angle φ can also be set to other angles, such as 30°, 45°, etc.
[0074] Reference Figure 4 and Figure 5 It is understandable that the second groove 3022 can be set as a continuous channel or as an intermittent structure formed by multiple groove segments along its own length direction. Both forms can promote the construction of lithium-ion transport channels.
[0075] In some embodiments of this application, a first groove 3021 and a second groove 3022 are also provided on the side of the curved section 302 away from the center of the battery cell body.
[0076] In this embodiment, by providing a first groove 3021 and a second groove 3022 on the outer side of the curved section 302, more lithium-ion transport channels can be constructed in conjunction with the outer electrode, thereby improving the charging and discharging capability.
[0077] It should be noted that, if necessary, a first groove 3021 and a second groove 3022 can also be provided in the straight section 301. Furthermore, the width, depth, and number of the first groove 3021 and the second groove 3022 can be set proportionally to the charging ratio of the wound battery cell; the higher the charging ratio, the larger the width, depth, and number should be.
[0078] Embodiments of this application also propose a battery comprising the wound cell of any of the above embodiments.
[0079] It is understandable that the battery in this application, by setting the first groove 3021 and the second groove 3022 at the corner, can effectively construct a lithium-ion transport channel, improve the lithium-ion transport capacity at the corner, thereby improving the charge and discharge capacity and reducing lithium plating at the corner. At the same time, the first groove 3021 and the second groove 3022 can reduce the thickness of the electrode sheet, which is beneficial to ensuring the energy density of the cell. Therefore, while taking into account energy density, it can alleviate lithium plating at the corner, solving the shortcomings of traditional methods.
[0080] The embodiments of this application have been described in detail above with reference to the accompanying drawings. However, this application is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of this application. Furthermore, unless otherwise specified, the embodiments and features described in the embodiments of this application can be combined with each other.
Claims
1. A wound battery cell, characterized in that, include: The battery cell body includes a positive electrode plate and a negative electrode plate, which are stacked and wound together. Along the winding direction, the positive electrode plate and the negative electrode plate include alternating straight sections and curved sections. Wherein, at least a portion of the bent section of the positive electrode and / or at least a portion of the bent section of the negative electrode are provided with a first groove and a second groove, the first groove being located at least on the side of the bent section near the center of the cell body, and the second groove being located on the groove wall of the first groove.
2. The wound battery cell according to claim 1, characterized in that, Along a direction away from the center of the battery cell body, the depth of the first groove decreases layer by layer.
3. The wound battery cell according to claim 1, characterized in that, The cross-sectional profile of the first groove in the width direction is at least one of V-shape, arc shape and U-shape.
4. The wound battery cell according to claim 1, characterized in that, Along the outer ring of the battery cell body towards the center, the maximum width of the first groove decreases or remains the same layer by layer.
5. The wound battery cell according to claim 1, characterized in that, Both the positive electrode and the negative electrode include a current collector and an active material layer. The active material layer is disposed on both sides of the current collector. The first groove and the second groove are both disposed on the active material layer, and the maximum depth of the first groove to the surface of the active material layer is [not specified]. The thickness H of the active material layer satisfies: 0.01H ≤ ≤0.5H.
6. The wound battery cell according to claim 1, characterized in that, Both the positive electrode and the negative electrode include a current collector and an active material layer. The active material layer is disposed on both sides of the current collector. The first groove and the second groove are both disposed on the active material layer, and the maximum depth of the second groove to the surface of the active material layer is... The thickness H of the active material layer satisfies: 0.2H ≤ ≤0.8H.
7. The wound battery cell according to claim 1, characterized in that, The curved section is provided with a plurality of first grooves along the winding direction, and / or, along the length direction of the curved section, a plurality of second grooves are provided in the first grooves.
8. The wound battery cell according to claim 1, characterized in that, The angle φ between the length direction of the second groove and the length direction of the first groove satisfies: 0°≤φ≤90°.
9. The wound battery cell according to claim 1, characterized in that, The curved section also has the first groove and the second groove on the side away from the center of the battery cell body.
10. A battery, characterized in that, Includes the wound battery cell as described in any one of claims 1 to 9.